crossbario autobahn-python up to 26.10.0 PerMessageBrotli compress_brotli.py PerMessageBrotli.decompress_message_data allocation of resources

Summaryinfo

A vulnerability classified as problematic has been found in crossbario autobahn-python up to 26.10.0. Affected by this issue is the function PerMessageBrotli.decompress_message_data of the file compress_brotli.py of the component PerMessageBrotli. The manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-116579. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in crossbario autobahn-python up to 26.10.0. This issue affects the function PerMessageBrotli.decompress_message_data of the file compress_brotli.py of the component PerMessageBrotli. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. The summary by CVE is:

Autobahn Python is a WebSocket and WAMP implementation for Python that supports Twisted and asyncio. From 26.7.1 until 26.10.1, PerMessageBrotli.decompress_message_data in compress_brotli.py calls the Brotli decompressor without an output limit and checks maxMessagePayloadSize only after a complete frame has been inflated. An unauthenticated WebSocket client can send a small, highly compressed frame that allocates hundreds of MiB before rejection, causing memory-exhaustion denial of service on servers that enable the opt-in permessage-brotli feature through the compress extra. Deflate and bzip2 already enforce the remaining output budget and are outside this residual vulnerability. This issue is fixed in version 26.10.1.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-116579 since 10/26/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 26.10.1 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• crossbario

Name

• autobahn-python

Version

• 26.0
• 26.1
• 26.2
• 26.3
• 26.4
• 26.5
• 26.6
• 26.7
• 26.8
• 26.9
• 26.10.0

Website

• Product: https://github.com/crossbario/autobahn-python/

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CPE 2.2info

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